1. Field of the Invention
The present invention relates to a loading/unloading mechanism for read and/or write head used in a disk drive apparatus which drives a disk recording medium, particularly, it relates to simplification of its structure.
2. Description of Related Arts
FIG. 1 is a plan view showing an example of a loading/unloading mechanism of a conventional disk drive apparatus published in "NIKKEI ELECTRONICS", 1986, 3-24, No. 391, pp 90 to pp 99, and FIG. 2 is a perspective view showing its structure. In the figure, numeral 1 indicates a sliding-type read and/or write head which reads and/or writes a magnetic disk 3. The read and/or write head 1 is installed on a tip of a tapered suspension 2 and supported thereon so as to be urged in a direction contacting to the magnetic disk 3. In the midway of the suspension 2, a cam 21 is engaged with a lifter 6 to be described later. The base end of the suspension 2 is mounted on an actuator 4 which swings about a pivot shaft 41. Actuator 4 is formed in a shape of a sickle and in the midway thereof, projects a strut 71 which serves as a rotating center of a link arm 7 supporting the lifter 6. The link arm 7 is provided with the bar lifter 6 on its one end, and on the other end, a cam pin 72 engaged with a latching cam 24 to be described later. The link arm 7 is urged counterclockwise by means of a spring 27, and the counterclockwise movement of the lifter 6 is regulated by a stopper pin 23 contacting its base end. The stopper pin 23 is movable up and down by a loading solenoid 22. The latching cam 24 is for retaining the lifter 6 in the vicinity of the root of the suspension 2, and is provided with a latch groove 24a engaged with the cam pin 72 on its periphery. The latching cam 24 swings about a pivot 24b and is usually urged counterclockwise by a latching spring 25. Thereby, the latching groove 24a and the cam pin 72 are kept in contact when they are engaged with each other. The latching cam 24 is rotated clockwise by a cam releasing solenoid 26 to release the engagement between the latch groove 24a and the cam pin 72.
Next, the loading and unloading operation for the conventional loading/unloading mechanism of the read and/or write head will be described.
Referring to FIG. 1, first, the case where the read and/or write head 1 moves from the unloading state in which it is detached from the magnetic disk 3, to the loading state in which it contacts to the magnetic disk 3 is described.
The actuator 4 is rotated about the pivot shaft 41 to bring the head 1 to the outermost periphery of the medium 3. Next, the solenoid 22 is energized to project the stopper pin 23. Then, while a portion of the link arm 7 to which the lifter 6 is fixed is caught by the pin 23, the actuator 4 is rotated reversely in an inner circumferential direction. At this time, since the strut 71 of the link arm 7 is fixed to the actuator 4, the link arm 7 is rotated in the opposite direction of the rotation of the actuator arm 4 or clockwise in FIG. 1, and the lifter 6 is moved in the releasing direction of the cam 21, disposed on the suspension 2. Thus, the head 1 is contacted to the magnetic disk 3 to achieve the loading state. The cam pin 72 is fixed to a portion of the link arm 7 and is moved to the position where it is caught by the latch groove 24a, provided on the cam 24, pre-loaded by the cam spring 25. Furthermore, the solenoid 22 is released and the pin 23 is retracted to complete the loading operation.
Next, the unloading operation for detaching the head 1 from the magnetic disk 3 is described. When the current preserved in a capacitor and the like, not shown, is applied to the cam releasing solenoid 26, installed on the actuator 4, as a result of the power source of the disk drive apparatus being cut off, a portion of the cam 24 is attracted and cam 24 is rotated clockwise, thereby the cam pin 72 caught by the latch groove 24a is released. As a result, the link arm 7 is rotated in the direction in which the lifter 6 approaches to the head 1 by the unloading spring 27, or counterclockwise in FIG. 1, and the head 1 is detached from the magnetic disk 3 to complete the unloading operation.
FIG. 3 is a perspective view showing a configuration of a conventional disk drive apparatus of a contact start and stop system (CSS), in which the read and/or write head is neither loaded nor unloaded. In the figure, numeral 31 designates a spindle motor which rotates the magnetic disk 3 and in the CSS system, keeps the read and/or write head 1 standstill on a shipping zone on the innermost periphery of the magnetic disk 3 at a time of non-operation. The read and/or write head 1 is installed on a tip of the suspension 2. The base end of the suspension 2 is mounted on a tip of the actuator 4. The actuator 4 swings about the pivot shaft 41.
When starting the disk drive apparatus of the CSS system, the spindle motor 31 is rotated while keeping the read and/or write head 1 standing still on the magnetic disk 3. In general, the head 1 is kept standstill at the inner circumference side on the magnetic disk 3. Though the head 1 rubs the magnetic disk 3 in the beginning, when a given revolution speed is achieved, it starts to float above the magnetic disk 3 by the air bearing effect. At normal revolution of the spindle motor, it floats at a constant height of about 0.2 .mu.m. When the disk drive apparatus is stopped and the revolution of the spindle motor reduces to a certain revolution speed, the head 1 begins to contact with the magnetic disk 3 and keeps rubbing the magnetic disk 3 until the spindle motor stops. Accordingly, it has been devised to stop the spindle motor positively for shortening the sliding distance.
Since the conventional head loading and unloading mechanism is constituted as aforementioned, the number of component parts increases, and it is necessary to insure a wide region for component parts and a region in which the lifter moves to unload the read and/or write head. Also, sequential operations for operating the component parts in constant order are necessitated, resulting in uncertainty of operation and frequent troubles. Moreover, there are such problems as complicated assembling and a high cost.
Meanwhile in the conventional CSS system, the lower the floating height of the read and/or write head from the magnetic disk, the less the frequency of contact start and stop, resulting in a shorter life. The higher the recording density the lower must be the floating height, resulting in the longer rubbing distance between the head and the magnetic disk thus causing problems. Also, as the head contacts directly to the medium the vibration and shock resistance at the time of non-operation is limited. Besides, when the number of magnetic disks increases and contact resistance of the read and/or write head therewith becomes larger, the starting torque of the spindle motor must be increased that much. In this system, since the motor is not reversible, angular position detecting means of certain accuracy must be provided in a spindle motor driving circuit. Furthermore, it is also necessary to provide means for reducing the idling time of the spindle motor at the time of interruption of the power source.